Problem: Simplify the following expression: ${-2(9+4z)+9(8z+3)}$
Solution: Distribute the ${-2}$ into the first set of parentheses: $ {-2(}\gray{9+4z}{)} + 9(8z+3) $ $ {-18-8z} + 9(8z+3) $ Distribute the ${9}$ into the parentheses: $ -18-8z + {9(}\gray{8z+3}{)} $ $ -18-8z + {72z+27} $ Rewrite the expression to group the ${z}$ terms and numeric terms: $ {-8z + 72z} {-18 + 27}$ Combine the ${z}$ terms: $ {64z} {-18 + 27}$ Combine the numeric terms: $ {64z} + {9}$ The simplified expression is $64z+9$